HIGHLY ENANTIOSELECTIVE INTRAMOLECULAR CYCLOPROPANATION REACTIONS OF N-ALLYLIC-N-METHYLDIAZOACETAMIDES CATALYZED BY CHIRAL DIRHODIUM(II) CARBOXAMIDATES

Catalytic diazo decomposition of representative N-allylic-N-methyldiaz oacetamides produced the corresponding intramolecular cyclopropanation products in good to excellent yields and with exceptional enantiocont rol. In the simplest case, with N-allyl-N-methyldiazoacetamide, cataly sis by dirhodium(II) tetrakis[methyl 2-oxapyrrolidine-5(S)-carboxylate ], Rh-2(5(S)-MEPY)(4), achieved the highest yield and enantioselectivi ty (93% eel. Dirhodium(II) tetrakis[methyl -(3-phenylpropanoyl)imidazo lidin-4(S)-carboxylate] Rh-2(4S)-MPPIM)(4), was preferred for substitu ted N-allylic-N-methyldiazoacetamides from which 92-95% ee's were obta ined in intramolecular cyclopropanation reactions (88-95% yields), eve n when the catalyst was employed in only 0.1 mol %, Competition with i ntramolecular dipolar cycloaddition was minimized with the use of N-me thyldiazoacetamides relative to N-tert-butyldiazoacetamides.